input.Nlevels = Gvars.Nlevels;
input.Nletters = Gvars.Nletters;
input.Ncodes = Gvars.Ncodes;
input.NLetterperRule = Gvars.NLetterperRule;

input.Nvertices = 4;
input.vertCoord = [-1 -1; 1 -1; 1 1; -1 1];